Dr. Zachary Erickson, Research Oceanographer, National Oceanic and Atmospheric Administration Pacific Marine Environmental Laboratory
Research Interests: Investigating the ocean’s role in the global carbon cycle; using data from ships, underwater robots, airplanes, and satellites to better understand how ocean physics (i.e., currents and the flow of water) affect marine biology and the storage of ocean carbon by phytoplankton.
Research Highlights: Regardless of how far you live from the ocean, phytoplankton, the microscopic plants that live in and serve as the primary building blocks of marine ecosystems, are responsible for almost half the oxygen you inhale. Through the process of photosynthesis, phytoplankton take up carbon dioxide from ocean waters, use it to grow and reproduce, and then release oxygen. In doing so, these tiny plants not only give us the oxygen we need to survive, but also play an important role in the Earth's carbon cycle.
However, unlike plants on land, phytoplankton don’t store much carbon because their populations often expand and contract in boom-and-bust cycles, wherein they quickly build-up in surface waters when nutrients are available or die-off when they aren't. Further, because phytoplankton aren’t anchored to any specific location, their periods of boom and bust depend on where they are in the ocean, and where they are depends on currents and the flow of ocean water.
The fate of the carbon contained within the phytoplankton depends on these currents and flows too, for if phytoplankton die and are re-mineralized at the surface—meaning the carbon within them turns back into carbon dioxide—then the ocean’s physical processes will return it back to the atmosphere. However, if phytoplankton die and then sink below the surface before being re-mineralized, or are consumed by other animals, the carbon they contain will be stored for a longer time. This transfer of carbon away from the surface and into the deeper ocean is called “carbon export,” and among the scientists working to gain a better understanding of the biological and physical ocean phenomena that affect it is Zachary Erickson, a Research Oceanographer with NOAA's Pacific Marine Environmental Laboratory (PMEL).
PMEL’s mission is to conduct innovative oceanographic and atmospheric research, observations, and technology development to address urgent global and regional environmental challenges. Erickson’s research focuses on physical dynamics, bio-physical interactions, and carbon export, which he investigates using long-term in-situ observations of temperature, salinity, oxygen, and other characteristics to understand how the ocean is evolving on decadal time scales. Erickson is also interested in integrating biological and optical oceanography measurements into observational platforms to understand bio-physical interactions in marine ecosystems and how they are responding to our changing environment.
To that end, Erickson says data from NASA and other sources are critical to helping him understand how the ocean’s physical processes impact marine biology and where carbon taken up by phytoplankton is ultimately stored.
“NASA Earth science data are crucial to many aspects of my work,” said Erickson. “I mostly use satellite observations of ocean color, which are provided by several NASA satellite instruments, such as the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument aboard NASA’s Aqua satellite and NASA's Sea-viewing Wide Field-of-view Sensor (SeaWiFS) instrument aboard GeoEye’s OrbView-2 (aka: SeaStar) satellite. NASA also stores in-situ data—data collected from sensors in the ocean—related to satellite remote sensing in its own data archive called the SeaWiFS Bio-optical Archive and Storage System (SeaBASS). I compare these data with those from satellites to help me decide if the equations used to derive information from satellite measurements of ocean color are correct.”
